Yesterday I wrote about using Fenwick rankings when the score is close to rank how good a team is. I want to compare this with a simpler team Corsi ranking. These are attempts to measure and quantify puck possession and use it to infer the ability of hockey team. To begin this study I want to present the raw data. Fenwick data is usually reported as a percentage of events (shots on goal and missed shots) that a team is responsible for. Corsi is usually listed as a +/- number (Corsi events for minus those against), thus we will be more concerned with relative rankings than with raw numbers.

Here are Fenwick close score rankings for teams compare with team Corsi rankings:

Close Score Fenwick Compared With Team Corsi 2011/12

Team

Fenwick Rank

Close Score Fenwick

Corsi Rank

Team Corsi

St Louis Blues

1

55.07%

9

+264

Pittsburgh Penguins

2

55.02%

2

+644

Detroit Red Wings

3

54.39%

1

+648

Los Angeles Kings

4

53.60%

3

+636

Chicago Blackhawks

5

52.82%

5

+412

Boston Bruins

6

52.60%

4

+547

San Jose Sharks

7

52.19%

8

+313

Vancouver Canucks

8

51.44%

6

+361

Philadelphia Flyers

9

51.14%

11

+172

New Jersey Devils

10

51.08%

13

-23

Winnipeg Jets

11

51.05%

12

+59

Ottawa Senators

12

50.90%

7

+360

Florida Panthers

13

50.35%

16

-89

New York Rangers

14

49.90%

25

-334

Colorado Avalanche

15

49.77%

10

+221

Washington Capitals

16

49.71%

19

-177

Dallas Stars

17

49.51%

15

-51

New York Islanders

18

49.18%

26

-351

Phoenix Coyotes

19

49.17%

14

-28

Tampa Bay Lightning

20

48.31%

29

-391

Carolina Hurricanes

21

48.17%

22

-280

Anaheim Ducks

22

48.12%

23

-286

Buffalo Sabres

23

48.10%

17

-140

Edmonton Oilers

24

48.08%

28

-387

Columbus Blue Jackets

25

47.53%

24

-306

Calgary Flames

26

47.47%

27

-386

Montreal Canadiens

27

46.81%

21

-258

Toronto Maple Leafs

28

46.70%

18

-163

Nashville Predators

29

46.08%

20

-186

Minnesota Wild

30

44.91%

30

-802

For the most part it is clear from looking at this chart we are measuring essentially the same number. The teams that do well by Fenwick close also do well by Team Corsi and vice versa. There are a few teams that have some difference between their ranking in both systems. These include the Fenwick leading St Louis Blues, the New York Rangers and Islanders, Toronto Maple Leafs and Nashville Predators. I think most of the remaining discrepancy is essentially meaningless error from the differences between the two systems. The difference in the rankings is minimal in these cases. Hence we learn something by looking at the five cases I have found as being most different.

The causes for discrepancy include the frequency and style of play of teams when a score is not close. Some teams are more competitive in games that are no longer close than others and some teams get into blow-out situations more often than others. There is also discrepancy due to shots blocked. Corsi includes these and Fenwick does not. This can have an effect in teams that block a lot of shots. I think a couple case studies in these teams with larger discrepancies between the two systems will be informative and I will do them in the future.